Convertible flat-bed cylinder arm sewing machine



N July 1, 1941- R. K. HOHMANN ETAL, 2,247,383

CONVERTIBLE FLAT-BED CYLINDER ARM SEWING MACHINE Original Filed Dec. 29, 1939 Patented July l, 194i CGNVERTIBLE FLAT-BED CYLINDER. ARM

SEWNG MACHINE Richard K. Hohmann, Jamaica, and Frederick Osann, White Plains, N. Y., assignors to Sears, Roebuck and (1o., Chicago, Ill., a, corporation of New York Original application December 29, 1939, Serial No. 3li,486. Divided and this application August 3, 1940, Serial No. 351,014

(Cl. i12-260) 3 Claims.

Our prior application Serial No. 311,486, of which. this application is a division, discloses a simple and eifective sewing machine devised by us for interchangeable use as a darning machine and for ordinary sewing operations.

That machine is readily convertible from one to the other of two conditions, in one of which it is adapted for plain sewing and includes a flat Work bed, which may be generally similar in form and disposition to the conventional work bed of a plain sewing machine, and in the other of which it is adapted for darning and is adapted to support stockings or other work to be darned, on a cylinder arm generally like, though preferably somewhat smaller in cross section than, the Work supporting cylinder arms of ordinary darning machines. In its preferred form, the machine is adapted, however, for either plain sewing or darning operations, on flat bed and cylinder arm supported work.

The general object of the present invention is to provide a sewing machine and a fiat Work bed part which can be readily -put Vin place in or'removed from the machine, of such character that with the Work bed part in place, has the general form and work supporting characteristics of an ordinary hat bed portable sewing machine, and with said part removed, the cylinder arm of the machine is fully exposed, and accessible for the free and unobstructed movements of stockings and other tubular work pieces onto and off said arm.

The various features of novelty which characterize the present invention are pointed out with particularity in the claims annexed to and form ing a part of this specification. For a better understanding of the invention, however, its

.advantages and specific objects attained with its use, reference should be had to the accompanying drawing and descriptiveY matter in which we have illustrated and described preferred forms of embodiment of the present invention.

Of the drawing:

Fig. l is an elevation, partly in section, of a sewing machine constituting a preferred embodiment of the present invention; p

Fig. 2 is a perspective view of the removable flat work bed member shown in Fig.

` Fig. 3' is a section on the line 3 3 of Fig. l with parts broken away and. removed;

Fig. i is a perspective view showing parts of the cylinder arm and flat Work bed of Fig'. i in section;

Fig. 5 is aview taken similarly to Fig. i, illustrating the use of a flat work bed member of modified form; and

Fig. 6 is a perspective view of the removable flat bed part shown in Fig. l.

The housing structure, or frame of the sewing l machine illustrated in the drawing, comprises a rectangular supporting bottom plate A, and a sewing machine body frame member which isscrew connected to the bottom plate and includes a rectangular base or bed portion A', a standard A2, and a horizontal cylinder arm comprising portions A5 and A6. The portion A5 is an integral tubular extension ot the base portion A', and A6 is a tubular part detachably secured to the front end of the part A5 and forming an extension of the latter.

The machine comprises a driving motor B, mounted in the base portion A' and having a pulley B on its shaft which is operatively connected Iby a belt C to a driving pulley D mounted on the adjacent end of the needle bar shaft E, which may be journalled in the arm A3 in any usual or suitable manner. In the preferred construction shown, the rear end E of the needle bar shaft E is threaded, and supports a nut member F,vwhich may be rotated about the shaft end E' to thereby clamp the hub portion of the pulley D between the head of the nut member F and the radially extending iiange of a part lil2 carried by and secured to the shaft E and com-- pulley D.

At its head end, the machine comprises means including a crank disc E4 carried by the shaft E for actuating a needle bar G, mounted in the head A4 in any usual or suitable manner for vertical reciprocatory movement. V

At its head end, the machine is also provided with a presser bar h, and in our said prior application we disclose and claim novel actuating means for lifting said presser bai` during each upstroke of the needle bar G, when the machine is in condition for darning use, but said actuabing meansneed not be illustrated or described herein. Our sewing machine also includes tension and thread take-up provisions which may be of conventional type and hence do not require description herein.

The sewing machine mechanism shown, is of the rotary hook type, and comprises a hook shaft I, which is suitably journalled in the frame part A' and its cylinder arm extension A5, and which carries a loop taker or hook element i adjacent the front of the machine. The hook shaft I is rotated bythe needle barshaft E through a vertical shaft I' journalled in the standard A2 and having its upper end connected to the shaft E by bevel gears 122 and having its lower end connected to the hook shaft I through bevel gears I3. Desirably, and as shown, the gears are so proportioned that the shaft I will rotate with double the angular velocity of the shaft E.

The sewing machine includes work feeding means comprising a fee'd dog K adapted to extend up into and to move horizontally in the slot of a throat or needle plate part KA, of conventional fiat form and supported by the cylinder arm part A6. The work feeding means also comprises mechanism within the hollow cylindrical arm of the sewing machine for giving the feed dog its feeding movements, but the character of said mechanism forms no part'of the invention claimed herein and need not be further referred to.

As shown in Fig. 3, the shaft of the motor B is parallel to the needle bar shaft E and hook shaft I, but is laterally displaced from the latter. To accommodate this displacement without requiring the standard A2 to have an unconventional and undesirable form, an idler pulley N, normally engaged by the rear run of the belt, is so located as to deflect the lower portion of that belt run into or near parallelism with the belt front run which extends in a direction inclined to the vertical from the pulley Bto the pulley D. In the normal operating position, the upper portion of the belt groove in the pulley D is within and closely encircled by a cylindrical portion A of the framework. An opening formed in the standard A2 and base member A', at the right hand end of 4the machine, as seen in Fig. .1, is normally closed by a removable cover plate or member A11, which is removable to permit access to the portion of the belt and other mechanism in Figs. 1 and 6, the member P is in the form of a metal box, minus its bottom wall, and open at its end which, when the` part is .in use as shown in Fig. 1, is adjacent and bears against the sewing machine frame part A. The part P is formed with an opening P' in its top wall to receive the throat plate member KA and with an adjacent openingP2 partly in the top wall and partly in the closed end member. The opening P2 is normally closed by a hinged cover member P3 which when moved into open position, permits access to the bobbin case extending into the loop taker, for insertion and removal of bobbins.

AA, and with the bed member P removed, no portion of the sewing machine obstructs movements of stockings or other tubular work parts onto and off the cylinder arm. As shown in Fig. 4, the tubular cylinder arm may advantageously be generally elliptical in cross section, but with its top portion flattened to provide a fiat seat for the engaging top portion of the member P.

In lieu of the fiat work bed part P shown in Figs. 1, 4 and 6, I may make use of the work bed part PA shown in Figs. 2 and 5. The part PA differs from the part P in that it is formed with a longitudinal slot P10 in its top wall adapted to receive the flattened top wall portion of the cylinder arm A50, which to this end may differ in shape from the cylinder arm'first described, in that its top wall portion vis in the form of a flat rib shaped to iit into the slot P10.

As shown, a bobbin winder wheel Q, carried by an arm Q' pivotally connected to the standard A2, is adapted to be turned from itsidle position, shown in Fig. 3'into the position in which the wheel Q extends through a slot formed for the purpose in the standard'A2, and frictionally engages the pulley D, which, during the bobbin winding operation is normally free to turn on the needle shaft E.

As previously stated, the machine may be used interchangeably in plain sewing and dai-ning op erations, either with the at bed part P or PA in place, or removed so that the work may be supported .on the cylinder arm. The flat bed parts P and PA are simple in form and easily put in place and removed. The sewing machine shown is of the portabletype, but our improvements disclosed and claimed herein are adapted for use in sewing machines of the cabinet type, or of the convertible cabinet and portable type disclosed in the copending application Ser. No. 313,507, filed January 12, 1940, by Richard K. Hohmann, one of the petitioners herein.

While in accordance with the provisions of the statutes, we haveillustrated and ydescribed the best form of embodiment of the invention now the appended claims and that in some cases certain features of our invention may be used to advantage without a corresponding use of other features.

Having now described our invention, what we claim and desire to secure by Letters Patent, is:

1. A sewing machine comprising in combination aframe including a base plate, a standard extending upward from the base plate adjacent one endl of the latter and a work supporting cylinder arm extending away from said standard toward the opposite end, of the base plate and spaced above the latter and a separable fiat bed member detachably mounted on and supported by said frame and comprising a flat bed portion adapted to extend over said cylinder arm and `a depending marginal portion adapted to engage said base plate adjacent its edge.

As shown, the base plate A is formed with an 2. A sewing machine as specified in claim 1 including an uprising needle plate supported on said cylinder arm, and in which said flat bed portion of the flat-bed member is formed with an opening adapted to receive said needle plate and in which said depending marginal portion of the flat bed member comprises side parts at opposite sides of said cylinder arm, and an end part transverse to said arm and at a distance tion in said at bed portion and another portion in said depending marginal portion, and in which vacover part is hinged to said iat bed member to move into and out of a posi-tion in whichy it closes said opening.

' RICHARD K. HOHMANN.

FREDERICK OSANN. 

